The continuing goal of this project is to promote a better understanding of the factors promoting mass transfer in the "exchanger" class of prosthetic devices. Specific objectives for this year are: a) to develop the coiled microporous tube oxygenator into a configuration appropriate for implantation within the chest. b) to assess geometric and mechanical factors responsible for the control of blood film thickness in "sheet flow" types of membrane oxygenators. c) to further evaluate the vascular graft component of prostheses attached to the cardiovascular system. d) to investigate the oxygen demand of freshly isolated cells (hepatocytes and Langerhans islets) implanted in a hybrid artificial organ. e) to sustain the prototype shop and the physiological laboratory which allow us to carry out such studies.